Field of the Invention
Embodiments of the present invention generally relate to transforming wide dynamic range images to reduced dynamic range images.
Description of the Related Art
The dynamic range of natural scenes can exceed three orders of magnitude. Camera sensors, especially the new wide dynamic range (WDR) sensors, can capture this range, providing a more natural image representation similar with the human vision system. WDR images, also referred to as high dynamic range (HDR) images, can achieve higher image quality due to a dynamic range that exceeds the more traditional 8, 10 and 12-bit images. Note that the term “dynamic range” described the ratio between the maximum and minimum measurable light intensities and is typically expressed as a bit depth in digital cameras and other devices. When WDR images are displayed on commonly used display devices, the images appear to be over-exposed in well-lighted scenes under-exposed in dark scenes. For example, display devices such as liquid crystal display (LCD) devices are limited to a dynamic range of roughly one to two orders of magnitude. Thus, details are lost when the images are displayed on such display devices. Typically, a tone mapping algorithm is used to adapt WDR images to the lower dynamic range of whatever display device is used.